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Posted to user@hadoop.apache.org by Sai Sai <sa...@yahoo.in> on 2013/03/28 05:01:50 UTC
Static class vs Normal Class when to use
In some examples/articles sometimes they use:
public static class MyMapper
and sometimes they use
public class MyMapper
When/why should we use static vs normal class.
Thanks
Sai
Re: Bloom Filter analogy in SQL
Posted by Ted <r6...@gmail.com>.
believe it or not, wikipedia has an excellent description of bloomfilters
http://en.wikipedia.org/wiki/Bloom_filter
On 4/16/13, Anupam Singh <av...@gmail.com> wrote:
> Many join implementations use bloom filters built on the smaller to
> eliminate rows on the larger tables in SQL queries. Many industrial RDBMS
> engines will show the use of bloom filters in SQL explain plans.
>
>
> For instance, oracle explain plans call these joins bloom filters as
> SYS_OP_BLOOM_FILTER :-
>
>
> https://forums.oracle.com/forums/thread.jspa?threadID=2470938
>
>
> It could be useful for performance tuning. Hope this helps.
>
>
> -Anupam
>
> —
> Sent from Mailbox for iPhone
>
> On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
> wrote:
>
>> This isn't a very Hadoop question.
>> A Bloom filter is a very low level data structure that doesn't really any
>> correlate in SQL. It allows you to find duplicates quickly and
>> probabilistically. In return for a small probability of a false
>> positive,
>> it uses less memory.
>> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>>> Can some one give a simple analogy of Bloom Filter in SQL.
>>> I am trying to understand and always get confused.
>>> Thanks
>>>
--
Ted.
Re: Bloom Filter analogy in SQL
Posted by Ted <r6...@gmail.com>.
believe it or not, wikipedia has an excellent description of bloomfilters
http://en.wikipedia.org/wiki/Bloom_filter
On 4/16/13, Anupam Singh <av...@gmail.com> wrote:
> Many join implementations use bloom filters built on the smaller to
> eliminate rows on the larger tables in SQL queries. Many industrial RDBMS
> engines will show the use of bloom filters in SQL explain plans.
>
>
> For instance, oracle explain plans call these joins bloom filters as
> SYS_OP_BLOOM_FILTER :-
>
>
> https://forums.oracle.com/forums/thread.jspa?threadID=2470938
>
>
> It could be useful for performance tuning. Hope this helps.
>
>
> -Anupam
>
> —
> Sent from Mailbox for iPhone
>
> On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
> wrote:
>
>> This isn't a very Hadoop question.
>> A Bloom filter is a very low level data structure that doesn't really any
>> correlate in SQL. It allows you to find duplicates quickly and
>> probabilistically. In return for a small probability of a false
>> positive,
>> it uses less memory.
>> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>>> Can some one give a simple analogy of Bloom Filter in SQL.
>>> I am trying to understand and always get confused.
>>> Thanks
>>>
--
Ted.
Re: Bloom Filter analogy in SQL
Posted by Ted <r6...@gmail.com>.
believe it or not, wikipedia has an excellent description of bloomfilters
http://en.wikipedia.org/wiki/Bloom_filter
On 4/16/13, Anupam Singh <av...@gmail.com> wrote:
> Many join implementations use bloom filters built on the smaller to
> eliminate rows on the larger tables in SQL queries. Many industrial RDBMS
> engines will show the use of bloom filters in SQL explain plans.
>
>
> For instance, oracle explain plans call these joins bloom filters as
> SYS_OP_BLOOM_FILTER :-
>
>
> https://forums.oracle.com/forums/thread.jspa?threadID=2470938
>
>
> It could be useful for performance tuning. Hope this helps.
>
>
> -Anupam
>
> —
> Sent from Mailbox for iPhone
>
> On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
> wrote:
>
>> This isn't a very Hadoop question.
>> A Bloom filter is a very low level data structure that doesn't really any
>> correlate in SQL. It allows you to find duplicates quickly and
>> probabilistically. In return for a small probability of a false
>> positive,
>> it uses less memory.
>> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>>> Can some one give a simple analogy of Bloom Filter in SQL.
>>> I am trying to understand and always get confused.
>>> Thanks
>>>
--
Ted.
Re: Bloom Filter analogy in SQL
Posted by Ted <r6...@gmail.com>.
believe it or not, wikipedia has an excellent description of bloomfilters
http://en.wikipedia.org/wiki/Bloom_filter
On 4/16/13, Anupam Singh <av...@gmail.com> wrote:
> Many join implementations use bloom filters built on the smaller to
> eliminate rows on the larger tables in SQL queries. Many industrial RDBMS
> engines will show the use of bloom filters in SQL explain plans.
>
>
> For instance, oracle explain plans call these joins bloom filters as
> SYS_OP_BLOOM_FILTER :-
>
>
> https://forums.oracle.com/forums/thread.jspa?threadID=2470938
>
>
> It could be useful for performance tuning. Hope this helps.
>
>
> -Anupam
>
> —
> Sent from Mailbox for iPhone
>
> On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
> wrote:
>
>> This isn't a very Hadoop question.
>> A Bloom filter is a very low level data structure that doesn't really any
>> correlate in SQL. It allows you to find duplicates quickly and
>> probabilistically. In return for a small probability of a false
>> positive,
>> it uses less memory.
>> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>>> Can some one give a simple analogy of Bloom Filter in SQL.
>>> I am trying to understand and always get confused.
>>> Thanks
>>>
--
Ted.
Re: Bloom Filter analogy in SQL
Posted by Anupam Singh <av...@gmail.com>.
Many join implementations use bloom filters built on the smaller to eliminate rows on the larger tables in SQL queries. Many industrial RDBMS engines will show the use of bloom filters in SQL explain plans.
For instance, oracle explain plans call these joins bloom filters as SYS_OP_BLOOM_FILTER :-
https://forums.oracle.com/forums/thread.jspa?threadID=2470938
It could be useful for performance tuning. Hope this helps.
-Anupam
—
Sent from Mailbox for iPhone
On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
wrote:
> This isn't a very Hadoop question.
> A Bloom filter is a very low level data structure that doesn't really any
> correlate in SQL. It allows you to find duplicates quickly and
> probabilistically. In return for a small probability of a false positive,
> it uses less memory.
> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>> Can some one give a simple analogy of Bloom Filter in SQL.
>> I am trying to understand and always get confused.
>> Thanks
>>
Re: Bloom Filter analogy in SQL
Posted by Anupam Singh <av...@gmail.com>.
Many join implementations use bloom filters built on the smaller to eliminate rows on the larger tables in SQL queries. Many industrial RDBMS engines will show the use of bloom filters in SQL explain plans.
For instance, oracle explain plans call these joins bloom filters as SYS_OP_BLOOM_FILTER :-
https://forums.oracle.com/forums/thread.jspa?threadID=2470938
It could be useful for performance tuning. Hope this helps.
-Anupam
—
Sent from Mailbox for iPhone
On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
wrote:
> This isn't a very Hadoop question.
> A Bloom filter is a very low level data structure that doesn't really any
> correlate in SQL. It allows you to find duplicates quickly and
> probabilistically. In return for a small probability of a false positive,
> it uses less memory.
> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>> Can some one give a simple analogy of Bloom Filter in SQL.
>> I am trying to understand and always get confused.
>> Thanks
>>
Re: Bloom Filter analogy in SQL
Posted by Anupam Singh <av...@gmail.com>.
Many join implementations use bloom filters built on the smaller to eliminate rows on the larger tables in SQL queries. Many industrial RDBMS engines will show the use of bloom filters in SQL explain plans.
For instance, oracle explain plans call these joins bloom filters as SYS_OP_BLOOM_FILTER :-
https://forums.oracle.com/forums/thread.jspa?threadID=2470938
It could be useful for performance tuning. Hope this helps.
-Anupam
—
Sent from Mailbox for iPhone
On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
wrote:
> This isn't a very Hadoop question.
> A Bloom filter is a very low level data structure that doesn't really any
> correlate in SQL. It allows you to find duplicates quickly and
> probabilistically. In return for a small probability of a false positive,
> it uses less memory.
> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>> Can some one give a simple analogy of Bloom Filter in SQL.
>> I am trying to understand and always get confused.
>> Thanks
>>
Re: Bloom Filter analogy in SQL
Posted by Anupam Singh <av...@gmail.com>.
Many join implementations use bloom filters built on the smaller to eliminate rows on the larger tables in SQL queries. Many industrial RDBMS engines will show the use of bloom filters in SQL explain plans.
For instance, oracle explain plans call these joins bloom filters as SYS_OP_BLOOM_FILTER :-
https://forums.oracle.com/forums/thread.jspa?threadID=2470938
It could be useful for performance tuning. Hope this helps.
-Anupam
—
Sent from Mailbox for iPhone
On Fri, Mar 29, 2013 at 11:32 PM, Ted Dunning <td...@maprtech.com>
wrote:
> This isn't a very Hadoop question.
> A Bloom filter is a very low level data structure that doesn't really any
> correlate in SQL. It allows you to find duplicates quickly and
> probabilistically. In return for a small probability of a false positive,
> it uses less memory.
> On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
>> Can some one give a simple analogy of Bloom Filter in SQL.
>> I am trying to understand and always get confused.
>> Thanks
>>
Re: Bloom Filter analogy in SQL
Posted by Ted Dunning <td...@maprtech.com>.
This isn't a very Hadoop question.
A Bloom filter is a very low level data structure that doesn't really any
correlate in SQL. It allows you to find duplicates quickly and
probabilistically. In return for a small probability of a false positive,
it uses less memory.
On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
Re: Bloom Filter analogy in SQL
Posted by Ted Dunning <td...@maprtech.com>.
This isn't a very Hadoop question.
A Bloom filter is a very low level data structure that doesn't really any
correlate in SQL. It allows you to find duplicates quickly and
probabilistically. In return for a small probability of a false positive,
it uses less memory.
On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
Re: Bloom Filter analogy in SQL
Posted by Kai Voigt <k...@123.org>.
http://billmill.org/bloomfilter-tutorial/ has nice explanation, and it links to the Wiki entry for further theory.
Am 07.05.2013 um 16:56 schrieb Tony Burton <TB...@SportingIndex.com>:
> There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
>
>
> From: Sai Sai [mailto:saigraph@yahoo.in]
> Sent: 29 March 2013 16:37
> To: user@hadoop.apache.org
> Subject: Re: Bloom Filter analogy in SQL
>
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
>
>
> *****************************************************************************
> P Pleaseconsider the environment before printing this email
>
>
> Inbound email has been scanned for viruses & spam
>
>
>
>
> *****************************************************************************
> P Please consider the environment before printing this email or attachments
>
>
> This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued and approved by Sporting Index Ltd.
>
>
> Outbound email has been scanned for viruses and SPAM
>
--
Kai Voigt
k@123.org
Re: Bloom Filter analogy in SQL
Posted by Kai Voigt <k...@123.org>.
http://billmill.org/bloomfilter-tutorial/ has nice explanation, and it links to the Wiki entry for further theory.
Am 07.05.2013 um 16:56 schrieb Tony Burton <TB...@SportingIndex.com>:
> There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
>
>
> From: Sai Sai [mailto:saigraph@yahoo.in]
> Sent: 29 March 2013 16:37
> To: user@hadoop.apache.org
> Subject: Re: Bloom Filter analogy in SQL
>
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
>
>
> *****************************************************************************
> P Pleaseconsider the environment before printing this email
>
>
> Inbound email has been scanned for viruses & spam
>
>
>
>
> *****************************************************************************
> P Please consider the environment before printing this email or attachments
>
>
> This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued and approved by Sporting Index Ltd.
>
>
> Outbound email has been scanned for viruses and SPAM
>
--
Kai Voigt
k@123.org
Re: Bloom Filter analogy in SQL
Posted by Kai Voigt <k...@123.org>.
http://billmill.org/bloomfilter-tutorial/ has nice explanation, and it links to the Wiki entry for further theory.
Am 07.05.2013 um 16:56 schrieb Tony Burton <TB...@SportingIndex.com>:
> There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
>
>
> From: Sai Sai [mailto:saigraph@yahoo.in]
> Sent: 29 March 2013 16:37
> To: user@hadoop.apache.org
> Subject: Re: Bloom Filter analogy in SQL
>
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
>
>
> *****************************************************************************
> P Pleaseconsider the environment before printing this email
>
>
> Inbound email has been scanned for viruses & spam
>
>
>
>
> *****************************************************************************
> P Please consider the environment before printing this email or attachments
>
>
> This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued and approved by Sporting Index Ltd.
>
>
> Outbound email has been scanned for viruses and SPAM
>
--
Kai Voigt
k@123.org
Re: Bloom Filter analogy in SQL
Posted by Kai Voigt <k...@123.org>.
http://billmill.org/bloomfilter-tutorial/ has nice explanation, and it links to the Wiki entry for further theory.
Am 07.05.2013 um 16:56 schrieb Tony Burton <TB...@SportingIndex.com>:
> There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
>
>
> From: Sai Sai [mailto:saigraph@yahoo.in]
> Sent: 29 March 2013 16:37
> To: user@hadoop.apache.org
> Subject: Re: Bloom Filter analogy in SQL
>
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
>
>
> *****************************************************************************
> P Pleaseconsider the environment before printing this email
>
>
> Inbound email has been scanned for viruses & spam
>
>
>
>
> *****************************************************************************
> P Please consider the environment before printing this email or attachments
>
>
> This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued and approved by Sporting Index Ltd.
>
>
> Outbound email has been scanned for viruses and SPAM
>
--
Kai Voigt
k@123.org
RE: Bloom Filter analogy in SQL
Posted by Tony Burton <TB...@SportingIndex.com>.
There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
From: Sai Sai [mailto:saigraph@yahoo.in]
Sent: 29 March 2013 16:37
To: user@hadoop.apache.org
Subject: Re: Bloom Filter analogy in SQL
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
*****************************************************************************
P Pleaseconsider the environment before printing this email
Inbound email has been scanned for viruses & spam
**********************************************************************
Please consider the environment before printing this email or attachments
This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued
and approved by Sporting Index Ltd.
Outbound email has been scanned for viruses and SPAM
Re: list of linux commands for hadoop
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering if there are a list of linux commands or any article which r needed for learning hadoop.
Thanks
Re: list of linux commands for hadoop
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering if there are a list of linux commands or any article which r needed for learning hadoop.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Ted Yu <yu...@gmail.com>.
>From http://msdn.microsoft.com/en-us/library/cc278097(v=sql.100).aspx :
The new technology employed is based on bitmap filters, also known as *Bloom
filters *(see *Bloom filter, *Wikipedia 2007,
http://en.wikipedia.org/wiki/Bloom_filter) ...
HBase uses bloom filters extensively. I can give references if you're
interested.
On Fri, Mar 29, 2013 at 9:36 AM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
RE: Bloom Filter analogy in SQL
Posted by Tony Burton <TB...@SportingIndex.com>.
There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
From: Sai Sai [mailto:saigraph@yahoo.in]
Sent: 29 March 2013 16:37
To: user@hadoop.apache.org
Subject: Re: Bloom Filter analogy in SQL
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
*****************************************************************************
P Pleaseconsider the environment before printing this email
Inbound email has been scanned for viruses & spam
**********************************************************************
Please consider the environment before printing this email or attachments
This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued
and approved by Sporting Index Ltd.
Outbound email has been scanned for viruses and SPAM
Re: Bloom Filter analogy in SQL
Posted by Ted Yu <yu...@gmail.com>.
>From http://msdn.microsoft.com/en-us/library/cc278097(v=sql.100).aspx :
The new technology employed is based on bitmap filters, also known as *Bloom
filters *(see *Bloom filter, *Wikipedia 2007,
http://en.wikipedia.org/wiki/Bloom_filter) ...
HBase uses bloom filters extensively. I can give references if you're
interested.
On Fri, Mar 29, 2013 at 9:36 AM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
Re: Bloom Filter analogy in SQL
Posted by Ted Yu <yu...@gmail.com>.
>From http://msdn.microsoft.com/en-us/library/cc278097(v=sql.100).aspx :
The new technology employed is based on bitmap filters, also known as *Bloom
filters *(see *Bloom filter, *Wikipedia 2007,
http://en.wikipedia.org/wiki/Bloom_filter) ...
HBase uses bloom filters extensively. I can give references if you're
interested.
On Fri, Mar 29, 2013 at 9:36 AM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
RE: Bloom Filter analogy in SQL
Posted by Tony Burton <TB...@SportingIndex.com>.
There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
From: Sai Sai [mailto:saigraph@yahoo.in]
Sent: 29 March 2013 16:37
To: user@hadoop.apache.org
Subject: Re: Bloom Filter analogy in SQL
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
*****************************************************************************
P Pleaseconsider the environment before printing this email
Inbound email has been scanned for viruses & spam
**********************************************************************
Please consider the environment before printing this email or attachments
This email and any attachments are confidential, protected by copyright and may be legally privileged. If you are not the intended recipient, then the dissemination or copying of this email is prohibited. If you have received this in error, please notify the sender by replying by email and then delete the email completely from your system. Neither Sporting Index nor the sender accepts responsibility for any virus, or any other defect which might affect any computer or IT system into which the email is received and/or opened. It is the responsibility of the recipient to scan the email and no responsibility is accepted for any loss or damage arising in any way from receipt or use of this email. Sporting Index Ltd is a company registered in England and Wales with company number 2636842, whose registered office is at Gateway House, Milverton Street, London, SE11 4AP. Sporting Index Ltd is authorised and regulated by the UK Financial Services Authority (reg. no. 150404) and Gambling Commission (reg. no. 000-027343-R-308898-001). Any financial promotion contained herein has been issued
and approved by Sporting Index Ltd.
Outbound email has been scanned for viruses and SPAM
Re: Bloom Filter analogy in SQL
Posted by Ted Dunning <td...@maprtech.com>.
This isn't a very Hadoop question.
A Bloom filter is a very low level data structure that doesn't really any
correlate in SQL. It allows you to find duplicates quickly and
probabilistically. In return for a small probability of a false positive,
it uses less memory.
On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
RE: Bloom Filter analogy in SQL
Posted by Tony Burton <TB...@SportingIndex.com>.
There’s an explanation of Bloom Filters and a MapReduce implementation in Chuck Lam’s book “Hadoop In Action”. Maybe that might guide the way a bit more.
From: Sai Sai [mailto:saigraph@yahoo.in]
Sent: 29 March 2013 16:37
To: user@hadoop.apache.org
Subject: Re: Bloom Filter analogy in SQL
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
*****************************************************************************
P Pleaseconsider the environment before printing this email
Inbound email has been scanned for viruses & spam
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Re: Bloom Filter analogy in SQL
Posted by Ted Dunning <td...@maprtech.com>.
This isn't a very Hadoop question.
A Bloom filter is a very low level data structure that doesn't really any
correlate in SQL. It allows you to find duplicates quickly and
probabilistically. In return for a small probability of a false positive,
it uses less memory.
On Fri, Mar 29, 2013 at 5:36 PM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
Re: list of linux commands for hadoop
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering if there are a list of linux commands or any article which r needed for learning hadoop.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Ted Yu <yu...@gmail.com>.
>From http://msdn.microsoft.com/en-us/library/cc278097(v=sql.100).aspx :
The new technology employed is based on bitmap filters, also known as *Bloom
filters *(see *Bloom filter, *Wikipedia 2007,
http://en.wikipedia.org/wiki/Bloom_filter) ...
HBase uses bloom filters extensively. I can give references if you're
interested.
On Fri, Mar 29, 2013 at 9:36 AM, Sai Sai <sa...@yahoo.in> wrote:
> Can some one give a simple analogy of Bloom Filter in SQL.
> I am trying to understand and always get confused.
> Thanks
>
Re: list of linux commands for hadoop
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering if there are a list of linux commands or any article which r needed for learning hadoop.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Sai Sai <sa...@yahoo.in>.
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Sai Sai <sa...@yahoo.in>.
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Sai Sai <sa...@yahoo.in>.
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
Re: Bloom Filter analogy in SQL
Posted by Sai Sai <sa...@yahoo.in>.
Can some one give a simple analogy of Bloom Filter in SQL.
I am trying to understand and always get confused.
Thanks
Re: Serialized comparator vs normal comparator
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering what is the difference between serialized comparator vs normal comparator given below,
the reason i am trying to understand this is how will you verify if you r using serialized comparator during debugging if the comparator is
working or not as when you debug in eclipse it shows byte info which cannot be understood by developers.
Here r the methods i am referring to:
/** A Comparator that compares serialized IntPair. */
public static class Comparator extends WritableComparator {
public Comparator() {
super(IntPair.class);
}
public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return compareBytes(b1, s1, l1, b2, s2, l2);
}
}
static { // register this comparator
WritableComparator.define(IntPair.class, new Comparator());
}
@Override
public int compareTo(IntPair o) {
if (first != o.first) {
return first < o.first ? -1 : 1;
} else if (second != o.second) {
return second < o.second ? -1 : 1;
} else {
return 0;
}
}
Re: Static class vs Normal Class when to use
Posted by Ted Dunning <td...@maprtech.com>.
Another Ted piping in.
For Hadoop use, it is dangerous to use anything but a static class for your
mapper and reducer functions since you may accidentally think that you can
access a closed variable from the parent. A static class cannot reference
those values so you know that you haven't made that mistake. If the mapper
or reducer class is not embedded in another class (i.e. not a member class)
then it is automatically static since there is nothing to inherit from.
Contrarily, static members in the mapper or reducer are real trouble unless
they are static final. The problem is that different mapper and reducer
invocations will see different values of these static values because they
are running in different JVM's. Dependence on statics is a common
beginner's mistake in Hadoop.
On Thu, Mar 28, 2013 at 6:01 AM, Sai Sai <sa...@yahoo.in> wrote:
> Hi Ted
> Thanks for your help it is really appreciated.
> I have gone thru the links that you have provided but i am looking for a
> simple exaplanation of using static classes in Hadoop/MR while
> syntactically i know how the static classes and variables r referred, i am
> wondering if there was something more than that we use static classes.
> In other words assuming static classes r loaded at the time the classes r
> loaded and not at the time the object is created and the timespan of
> objects of static classes r less than normal classes. Please let me know if
> this make sense and provide any additional info if you could.
> Thanks again.
> Sai
>
>
> ------------------------------
> *From:* Ted Yu <yu...@gmail.com>
> *To:* user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
> *Sent:* Thursday, 28 March 2013 9:41 AM
> *Subject:* Re: Static class vs Normal Class when to use
>
> Take a look at Effective Java 2nd edition:
> Item 22: Favor static member classes over nonstatic
>
> On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
>
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
>
>
>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Dunning <td...@maprtech.com>.
Another Ted piping in.
For Hadoop use, it is dangerous to use anything but a static class for your
mapper and reducer functions since you may accidentally think that you can
access a closed variable from the parent. A static class cannot reference
those values so you know that you haven't made that mistake. If the mapper
or reducer class is not embedded in another class (i.e. not a member class)
then it is automatically static since there is nothing to inherit from.
Contrarily, static members in the mapper or reducer are real trouble unless
they are static final. The problem is that different mapper and reducer
invocations will see different values of these static values because they
are running in different JVM's. Dependence on statics is a common
beginner's mistake in Hadoop.
On Thu, Mar 28, 2013 at 6:01 AM, Sai Sai <sa...@yahoo.in> wrote:
> Hi Ted
> Thanks for your help it is really appreciated.
> I have gone thru the links that you have provided but i am looking for a
> simple exaplanation of using static classes in Hadoop/MR while
> syntactically i know how the static classes and variables r referred, i am
> wondering if there was something more than that we use static classes.
> In other words assuming static classes r loaded at the time the classes r
> loaded and not at the time the object is created and the timespan of
> objects of static classes r less than normal classes. Please let me know if
> this make sense and provide any additional info if you could.
> Thanks again.
> Sai
>
>
> ------------------------------
> *From:* Ted Yu <yu...@gmail.com>
> *To:* user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
> *Sent:* Thursday, 28 March 2013 9:41 AM
> *Subject:* Re: Static class vs Normal Class when to use
>
> Take a look at Effective Java 2nd edition:
> Item 22: Favor static member classes over nonstatic
>
> On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
>
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
>
>
>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Dunning <td...@maprtech.com>.
Another Ted piping in.
For Hadoop use, it is dangerous to use anything but a static class for your
mapper and reducer functions since you may accidentally think that you can
access a closed variable from the parent. A static class cannot reference
those values so you know that you haven't made that mistake. If the mapper
or reducer class is not embedded in another class (i.e. not a member class)
then it is automatically static since there is nothing to inherit from.
Contrarily, static members in the mapper or reducer are real trouble unless
they are static final. The problem is that different mapper and reducer
invocations will see different values of these static values because they
are running in different JVM's. Dependence on statics is a common
beginner's mistake in Hadoop.
On Thu, Mar 28, 2013 at 6:01 AM, Sai Sai <sa...@yahoo.in> wrote:
> Hi Ted
> Thanks for your help it is really appreciated.
> I have gone thru the links that you have provided but i am looking for a
> simple exaplanation of using static classes in Hadoop/MR while
> syntactically i know how the static classes and variables r referred, i am
> wondering if there was something more than that we use static classes.
> In other words assuming static classes r loaded at the time the classes r
> loaded and not at the time the object is created and the timespan of
> objects of static classes r less than normal classes. Please let me know if
> this make sense and provide any additional info if you could.
> Thanks again.
> Sai
>
>
> ------------------------------
> *From:* Ted Yu <yu...@gmail.com>
> *To:* user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
> *Sent:* Thursday, 28 March 2013 9:41 AM
> *Subject:* Re: Static class vs Normal Class when to use
>
> Take a look at Effective Java 2nd edition:
> Item 22: Favor static member classes over nonstatic
>
> On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
>
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
>
>
>
>
>
Re: Serialized comparator vs normal comparator
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering what is the difference between serialized comparator vs normal comparator given below,
the reason i am trying to understand this is how will you verify if you r using serialized comparator during debugging if the comparator is
working or not as when you debug in eclipse it shows byte info which cannot be understood by developers.
Here r the methods i am referring to:
/** A Comparator that compares serialized IntPair. */
public static class Comparator extends WritableComparator {
public Comparator() {
super(IntPair.class);
}
public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return compareBytes(b1, s1, l1, b2, s2, l2);
}
}
static { // register this comparator
WritableComparator.define(IntPair.class, new Comparator());
}
@Override
public int compareTo(IntPair o) {
if (first != o.first) {
return first < o.first ? -1 : 1;
} else if (second != o.second) {
return second < o.second ? -1 : 1;
} else {
return 0;
}
}
Re: Serialized comparator vs normal comparator
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering what is the difference between serialized comparator vs normal comparator given below,
the reason i am trying to understand this is how will you verify if you r using serialized comparator during debugging if the comparator is
working or not as when you debug in eclipse it shows byte info which cannot be understood by developers.
Here r the methods i am referring to:
/** A Comparator that compares serialized IntPair. */
public static class Comparator extends WritableComparator {
public Comparator() {
super(IntPair.class);
}
public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return compareBytes(b1, s1, l1, b2, s2, l2);
}
}
static { // register this comparator
WritableComparator.define(IntPair.class, new Comparator());
}
@Override
public int compareTo(IntPair o) {
if (first != o.first) {
return first < o.first ? -1 : 1;
} else if (second != o.second) {
return second < o.second ? -1 : 1;
} else {
return 0;
}
}
Re: Serialized comparator vs normal comparator
Posted by Sai Sai <sa...@yahoo.in>.
Just wondering what is the difference between serialized comparator vs normal comparator given below,
the reason i am trying to understand this is how will you verify if you r using serialized comparator during debugging if the comparator is
working or not as when you debug in eclipse it shows byte info which cannot be understood by developers.
Here r the methods i am referring to:
/** A Comparator that compares serialized IntPair. */
public static class Comparator extends WritableComparator {
public Comparator() {
super(IntPair.class);
}
public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return compareBytes(b1, s1, l1, b2, s2, l2);
}
}
static { // register this comparator
WritableComparator.define(IntPair.class, new Comparator());
}
@Override
public int compareTo(IntPair o) {
if (first != o.first) {
return first < o.first ? -1 : 1;
} else if (second != o.second) {
return second < o.second ? -1 : 1;
} else {
return 0;
}
}
Re: Static class vs Normal Class when to use
Posted by Ted Dunning <td...@maprtech.com>.
Another Ted piping in.
For Hadoop use, it is dangerous to use anything but a static class for your
mapper and reducer functions since you may accidentally think that you can
access a closed variable from the parent. A static class cannot reference
those values so you know that you haven't made that mistake. If the mapper
or reducer class is not embedded in another class (i.e. not a member class)
then it is automatically static since there is nothing to inherit from.
Contrarily, static members in the mapper or reducer are real trouble unless
they are static final. The problem is that different mapper and reducer
invocations will see different values of these static values because they
are running in different JVM's. Dependence on statics is a common
beginner's mistake in Hadoop.
On Thu, Mar 28, 2013 at 6:01 AM, Sai Sai <sa...@yahoo.in> wrote:
> Hi Ted
> Thanks for your help it is really appreciated.
> I have gone thru the links that you have provided but i am looking for a
> simple exaplanation of using static classes in Hadoop/MR while
> syntactically i know how the static classes and variables r referred, i am
> wondering if there was something more than that we use static classes.
> In other words assuming static classes r loaded at the time the classes r
> loaded and not at the time the object is created and the timespan of
> objects of static classes r less than normal classes. Please let me know if
> this make sense and provide any additional info if you could.
> Thanks again.
> Sai
>
>
> ------------------------------
> *From:* Ted Yu <yu...@gmail.com>
> *To:* user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
> *Sent:* Thursday, 28 March 2013 9:41 AM
> *Subject:* Re: Static class vs Normal Class when to use
>
> Take a look at Effective Java 2nd edition:
> Item 22: Favor static member classes over nonstatic
>
> On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
>
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
>
>
>
>
>
Re: Static class vs Normal Class when to use
Posted by Sai Sai <sa...@yahoo.in>.
Hi Ted
Thanks for your help it is really appreciated.
I have gone thru the links that you have provided but i am looking for a simple exaplanation of using static classes in Hadoop/MR while
syntactically i know how the static classes and variables r referred, i am wondering if there was something more than that we use static classes.
In other words assuming static classes r loaded at the time the classes r loaded and not at the time the object is created and the timespan of objects of static classes r less than normal classes. Please let me know if this make sense and provide any additional info if you could.
Thanks again.
Sai
________________________________
From: Ted Yu <yu...@gmail.com>
To: user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
Sent: Thursday, 28 March 2013 9:41 AM
Subject: Re: Static class vs Normal Class when to use
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
See http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
>
>I believe Josh Bloch covers this in his famous book.
>
>
>
>On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>In some examples/articles sometimes they use:
>>public static class MyMapper
>>
>>
>>and sometimes they use
>>
>>
>>public class MyMapper
>>
>>
>>
>>When/why should we use static vs normal class.
>>
>>
>>ThanksSai
>
Re: Inspect a context object and see whats in it
Posted by Yanbo Liang <ya...@gmail.com>.
You can try to add some probes to source code and recompile it.
If you want to know the keys and values you add at each step, you can add
print code to map() function of class Mapper and reduce() function of class
Reducer.
The shortcoming is that you will produce many log output which may fill the
whole screen.
2013/3/28 Sai Sai <sa...@yahoo.in>
> I have put a break pt in map/reduce method and tried looking thru the
> context object by using the option inspect
> i see a lot of variables inside it but wondering if it is possible to look
> at the contents in it meaningfully
> by contents i mean the keys and values only that we add at each step.
> Please let me know if you have suggestions.
> Thanks
> Sai
>
Re: Inspect a context object and see whats in it
Posted by Yanbo Liang <ya...@gmail.com>.
You can try to add some probes to source code and recompile it.
If you want to know the keys and values you add at each step, you can add
print code to map() function of class Mapper and reduce() function of class
Reducer.
The shortcoming is that you will produce many log output which may fill the
whole screen.
2013/3/28 Sai Sai <sa...@yahoo.in>
> I have put a break pt in map/reduce method and tried looking thru the
> context object by using the option inspect
> i see a lot of variables inside it but wondering if it is possible to look
> at the contents in it meaningfully
> by contents i mean the keys and values only that we add at each step.
> Please let me know if you have suggestions.
> Thanks
> Sai
>
Re: Inspect a context object and see whats in it
Posted by Yanbo Liang <ya...@gmail.com>.
You can try to add some probes to source code and recompile it.
If you want to know the keys and values you add at each step, you can add
print code to map() function of class Mapper and reduce() function of class
Reducer.
The shortcoming is that you will produce many log output which may fill the
whole screen.
2013/3/28 Sai Sai <sa...@yahoo.in>
> I have put a break pt in map/reduce method and tried looking thru the
> context object by using the option inspect
> i see a lot of variables inside it but wondering if it is possible to look
> at the contents in it meaningfully
> by contents i mean the keys and values only that we add at each step.
> Please let me know if you have suggestions.
> Thanks
> Sai
>
Re: Inspect a context object and see whats in it
Posted by Yanbo Liang <ya...@gmail.com>.
You can try to add some probes to source code and recompile it.
If you want to know the keys and values you add at each step, you can add
print code to map() function of class Mapper and reduce() function of class
Reducer.
The shortcoming is that you will produce many log output which may fill the
whole screen.
2013/3/28 Sai Sai <sa...@yahoo.in>
> I have put a break pt in map/reduce method and tried looking thru the
> context object by using the option inspect
> i see a lot of variables inside it but wondering if it is possible to look
> at the contents in it meaningfully
> by contents i mean the keys and values only that we add at each step.
> Please let me know if you have suggestions.
> Thanks
> Sai
>
Re: Inspect a context object and see whats in it
Posted by Sai Sai <sa...@yahoo.in>.
I have put a break pt in map/reduce method and tried looking thru the context object by using the option inspect
i see a lot of variables inside it but wondering if it is possible to look at the contents in it meaningfully
by contents i mean the keys and values only that we add at each step.
Please let me know if you have suggestions.
Thanks
Sai
Re: Inspect a context object and see whats in it
Posted by Sai Sai <sa...@yahoo.in>.
I have put a break pt in map/reduce method and tried looking thru the context object by using the option inspect
i see a lot of variables inside it but wondering if it is possible to look at the contents in it meaningfully
by contents i mean the keys and values only that we add at each step.
Please let me know if you have suggestions.
Thanks
Sai
Re: Static class vs Normal Class when to use
Posted by Sai Sai <sa...@yahoo.in>.
Hi Ted
Thanks for your help it is really appreciated.
I have gone thru the links that you have provided but i am looking for a simple exaplanation of using static classes in Hadoop/MR while
syntactically i know how the static classes and variables r referred, i am wondering if there was something more than that we use static classes.
In other words assuming static classes r loaded at the time the classes r loaded and not at the time the object is created and the timespan of objects of static classes r less than normal classes. Please let me know if this make sense and provide any additional info if you could.
Thanks again.
Sai
________________________________
From: Ted Yu <yu...@gmail.com>
To: user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
Sent: Thursday, 28 March 2013 9:41 AM
Subject: Re: Static class vs Normal Class when to use
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
See http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
>
>I believe Josh Bloch covers this in his famous book.
>
>
>
>On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>In some examples/articles sometimes they use:
>>public static class MyMapper
>>
>>
>>and sometimes they use
>>
>>
>>public class MyMapper
>>
>>
>>
>>When/why should we use static vs normal class.
>>
>>
>>ThanksSai
>
Re: Inspect a context object and see whats in it
Posted by Sai Sai <sa...@yahoo.in>.
I have put a break pt in map/reduce method and tried looking thru the context object by using the option inspect
i see a lot of variables inside it but wondering if it is possible to look at the contents in it meaningfully
by contents i mean the keys and values only that we add at each step.
Please let me know if you have suggestions.
Thanks
Sai
Re: Static class vs Normal Class when to use
Posted by Sai Sai <sa...@yahoo.in>.
Hi Ted
Thanks for your help it is really appreciated.
I have gone thru the links that you have provided but i am looking for a simple exaplanation of using static classes in Hadoop/MR while
syntactically i know how the static classes and variables r referred, i am wondering if there was something more than that we use static classes.
In other words assuming static classes r loaded at the time the classes r loaded and not at the time the object is created and the timespan of objects of static classes r less than normal classes. Please let me know if this make sense and provide any additional info if you could.
Thanks again.
Sai
________________________________
From: Ted Yu <yu...@gmail.com>
To: user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
Sent: Thursday, 28 March 2013 9:41 AM
Subject: Re: Static class vs Normal Class when to use
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
See http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
>
>I believe Josh Bloch covers this in his famous book.
>
>
>
>On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>In some examples/articles sometimes they use:
>>public static class MyMapper
>>
>>
>>and sometimes they use
>>
>>
>>public class MyMapper
>>
>>
>>
>>When/why should we use static vs normal class.
>>
>>
>>ThanksSai
>
Re: Static class vs Normal Class when to use
Posted by Sai Sai <sa...@yahoo.in>.
Hi Ted
Thanks for your help it is really appreciated.
I have gone thru the links that you have provided but i am looking for a simple exaplanation of using static classes in Hadoop/MR while
syntactically i know how the static classes and variables r referred, i am wondering if there was something more than that we use static classes.
In other words assuming static classes r loaded at the time the classes r loaded and not at the time the object is created and the timespan of objects of static classes r less than normal classes. Please let me know if this make sense and provide any additional info if you could.
Thanks again.
Sai
________________________________
From: Ted Yu <yu...@gmail.com>
To: user@hadoop.apache.org; Sai Sai <sa...@yahoo.in>
Sent: Thursday, 28 March 2013 9:41 AM
Subject: Re: Static class vs Normal Class when to use
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
See http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
>
>I believe Josh Bloch covers this in his famous book.
>
>
>
>On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>In some examples/articles sometimes they use:
>>public static class MyMapper
>>
>>
>>and sometimes they use
>>
>>
>>public class MyMapper
>>
>>
>>
>>When/why should we use static vs normal class.
>>
>>
>>ThanksSai
>
Re: Inspect a context object and see whats in it
Posted by Sai Sai <sa...@yahoo.in>.
I have put a break pt in map/reduce method and tried looking thru the context object by using the option inspect
i see a lot of variables inside it but wondering if it is possible to look at the contents in it meaningfully
by contents i mean the keys and values only that we add at each step.
Please let me know if you have suggestions.
Thanks
Sai
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>> In some examples/articles sometimes they use:
>> public static class MyMapper
>>
>> and sometimes they use
>>
>> public class MyMapper
>>
>> When/why should we use static vs normal class.
>>
>> Thanks
>> Sai
>>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>> In some examples/articles sometimes they use:
>> public static class MyMapper
>>
>> and sometimes they use
>>
>> public class MyMapper
>>
>> When/why should we use static vs normal class.
>>
>> Thanks
>> Sai
>>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>> In some examples/articles sometimes they use:
>> public static class MyMapper
>>
>> and sometimes they use
>>
>> public class MyMapper
>>
>> When/why should we use static vs normal class.
>>
>> Thanks
>> Sai
>>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
Take a look at Effective Java 2nd edition:
Item 22: Favor static member classes over nonstatic
On Wed, Mar 27, 2013 at 9:05 PM, Ted Yu <yu...@gmail.com> wrote:
> See
> http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
>
> I believe Josh Bloch covers this in his famous book.
>
>
> On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
>
>> In some examples/articles sometimes they use:
>> public static class MyMapper
>>
>> and sometimes they use
>>
>> public class MyMapper
>>
>> When/why should we use static vs normal class.
>>
>> Thanks
>> Sai
>>
>
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
See
http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
I believe Josh Bloch covers this in his famous book.
On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
See
http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
I believe Josh Bloch covers this in his famous book.
On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
See
http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
I believe Josh Bloch covers this in his famous book.
On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>
Re: Static class vs Normal Class when to use
Posted by Ted Yu <yu...@gmail.com>.
See
http://stackoverflow.com/questions/1353309/java-static-vs-non-static-inner-class
I believe Josh Bloch covers this in his famous book.
On Wed, Mar 27, 2013 at 9:01 PM, Sai Sai <sa...@yahoo.in> wrote:
> In some examples/articles sometimes they use:
> public static class MyMapper
>
> and sometimes they use
>
> public class MyMapper
>
> When/why should we use static vs normal class.
>
> Thanks
> Sai
>